Crocs® states these shoes should fit very loosely. The sides of your foot should not really touch the sides of the shoe. Your toes should never make contact with the front of the shoe. Once you have centered your foot on the footbed: You should have about a 1/4 to 1/2 inch of space in front of your toes, behind your heel, and when you lift the strap you should be able to comfortably get your finger between the strap and heel.